How to subtract 1 week from Easter Date in php


I have been trying to get php to subtract 1 week from Easter and the outputs are just downright bizarre.

This is what I currently have

    $year = date("Y");
    $easterdate = date('d-m-y',easter_date($year));
    $newdate = strtotime('-7 days', strtotime($easterdate)); 
<?php echo $newdate;?> <br>
<?php echo $easterdate;?> <br>

The output I get is

newdate = 14-04-04
easterdate = 04-04-21

For some reason (which maybe very obvious that I can’t see) is that when I try to calculate the minus 7 days, it subtracts the years and reformats it to Y-M-D.

I have reviewed the other forum questions about subtracting time and have tried various methods including the site.

Source: Ask PHP